Just a small suggestion. When scrolling through the images on an attached post, the nav arrows move in order to be central to the image being displayed. This means when there are images of different sizes being displayed, the nav arrows move away from the mouse pointer. When using a widescreen monitor like I am, it detracts from the viewing experience as I have to keep looking for the arrow to move to the next image.
Better to centre the image in the view window / slideshow and leave the arrows in a fixed position. Since image viewing is pretty much a fullscreen affair, there are no drawbacks to doing it this way.